Imagine having a knee replacement and being able to point your phone at it to open an app that shows the level of stress on the artificial joint. Understanding which activities place the most strain—potentially leading to a second surgery—would be extremely valuable. Research led by Binghamton University is bringing this technology closer to reality.
Professor Shahrzad “Sherry” Towfighian, from the Department of Mechanical Engineering at the Thomas J. Watson College of Engineering and Applied Science, has spent the past decade developing “smart knee” technology.
Rising Demand for Knee Replacements Driven by Aging and Injuries
The American College of Rheumatology reports that nearly 800,000 total knee replacements are performed annually in the U.S., with numbers expected to increase significantly by 2030 as the population ages and sports-related injuries become more frequent.
“These implants are designed to last a lifetime, yet one in five patients experiences loosening or imbalance,” Towfighian said. “Without sensors to detect issues early, treatment often comes too late. Noninvasive load monitoring could enable earlier detection and better treatment.”
These sensors would be powered by piezoelectric and triboelectric transducers that convert the knee’s motion into small amounts of energy.
Recent studies by Towfighian and Ph.D. candidates Mahmood Chahari, Osama Abdalla, and Elham Mahmoudi—published in Nano Energy, Sensors, and IEEE/ASME Transactions on Mechatronics—explore optimal materials and designs for load sensors that rely on energy harvesting.
Hybrid Energy Generation Enhances Smart Knee Sensor Performance
For optimal performance, “smart knee” implants appear to benefit from combining triboelectric generation—produced when surfaces come into contact or slide—and piezoelectric generation, which depends on pressure and vibrations. The choice of materials also influences the sensitivity of the sensors.
“Since the harvester’s output is directly related to the load applied, it can function both as a sensor and a power source,” Towfighian explained. “With modern power management and wireless communication systems operating within the microwatt range generated, developing a self-powered load sensor is feasible.”
The research also involves collaborators from Stony Brook University and Western University in London, Canada.
Validation Through Advanced Simulation and Next-Phase Testing
“We validated our results using a joint simulator by Associate Professor Ryan Willing at Western University that replicates the knee’s six degrees of freedom,” Towfighian said. We’re confident in the device’s performance so far. The next step is sealing the system and testing it on cadaver legs for biocompatibility and sensor accuracy.
Read the original article on:medicalxpress
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